A Mesa teenager pleaded not guilty Wednesday to charges he beat and killed his mother with a frying pan and hammer, according to Maricopa County Superior Court.

Michael Helms, 16, faces a series of charges, including first-degree murder, attempted first-degree murder and aggravated assault in the death of his mother, 36-year-old Tina Helms Spencer, and the attack on his stepfather.

Christian Lee Blakely, 17, also pleaded not guilty Wednesday. Blakely is suspected of helping Helms. He faces charges including first-degree murder, conspiracy to commit first-degree murder and tampering with evidence.

The ordeal began when Helms reportedly announced his parents had moved to Ohio and left him their home just south of U.S. 60 and east of Gilbert Road.

Helms was arrested a day later on suspicion of murdering his mother, who had angered him when she grounded him, according to Mesa police. His mother was found dead in the backyard shed.

A Gilbert police report released Wednesday sheds additional light on why Tina Helms Spencer may have grounded her son. It indicates that Michael Helms not only forged her signature on a form in an attempt to get free school lunches without her knowledge, but also concocted a forged note that supposedly was written by his guidance counselor at Gilbert High School, identified in the report as Robert Forti.

Helms wrote the note in orange ink and signed it with Forti’s name in hopes that a teacher, Amie Fowler, would allow him to work as her assistant. Fowler required that Helms obtain written permission from Forti to work as a teacher’s assistant.

But the report said Fowler immediately became suspicious and went to Gilbert High School administrators because “the note had several spelling errors with several of the words crossed out.”

When confronted with the crudely forged note, Helms admitted that he was the person who wrote it, not Forti, the report said. He was detained as a juvenile, but was not prosecuted in the Juvenile Division of Superior Court because Forti did not want to cooperate and “stated that the school’s punishment would be sufficient.’’

Mesa police have said Michael Helms had become angry at his mother for disciplining him after he got in trouble at school. In both forgery incidents, one in September and the other in October days before the slaying, police notified Helms Spencer about the incidents.

The county Medical Examiner’s Office concluded through an autopsy that Helms Spencer was murdered and that she died from blunt-force trauma inflicted with multiple blows to her head with a hammer and a frying pan.

Blakely was also arrested on suspicion of witnessing the murder and helping Helms transport the body, according to police.

Authorities said they suspect Helms and Blakely waited at the family’s house near Baseline and Gilbert roads until Helms Spencer arrived, according to Maricopa County Court records

“As the victim entered her residence, the defendant then intentionally struck her with a frying pan, struck her with a hammer, and choked her in a rage,” according to court records.

Helms’ stepfather called police at 4 a.m. from a neighboring home saying his stepson attacked him when he arrived home early Saturday morning.

He thought his wife was asleep, but when police arrived, they found blood and eventually found Helms Spencer in the shed. Helms had quarreled with his mother during a telephone call before she was slain, according to police.

Police said Helms told Blakely he was planning to kill his mother.

Blakely’s court records said he “stood in the dark and watched as the murder occurred.”

Blakely admitted to watching the crime and helping Helms clean up the house with a mop, according to documents.

The documents said that Helms confirmed many details but added that Blakely helped him drag Helms Spencer’s body to the shed.

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